Over 150,000 amputations occur in the United States annually. Amputations are rising in frequency due to diabetes and peripheral vascular disease. The transtibial level of amputation is the most frequently performed.
A transtibial amputation is an amputation of the lower limb below the knee. A transtibial prosthesis is an artificial limb that replaces the portion of the leg below the knee that is missing. The shape of the residual limb varies for each individual and generally requires a custom-filled prosthesis. A custom-fitted prosthesis that is comfortable is difficult to fabricate and costly.
The initial cost of a conventional prosthesis for a transtibial amputee typically ranges from $6000 to $14,000. In addition, there are additional costs to ensure the comfort and functionality of the device. The present state of prosthesis fabrication often requires three or more visits to the prosthetist and there are multiple steps in the fabrication process. First, a cast mold of the residual limb is made and a positive cast that resembles the residual limb is generated. Then, a prosthetic socket is built to custom-fit over the positive cast. Sometimes a check or temporary socket is made to insure a better fit. Typical fabrication techniques require specialized facilities. Generally, the final prosthesis requires post-fabrication adjustments as the residual limb tissue changes over time.
Recent advancements have been made in the field of prosthetic devices. However, devices such as computerized knee mechanisms and energy storing feet are costly and beyond the economic means of the majority of prosthetic users, particularly those in nations outside the United States.
Attempts have been made in the prior art to develop prosthesis systems that can be globally manufactured and distributed. These prosthesis systems, however, have several limitations. They are difficult to fabricate and require specialized facilities for initial manufacturing (e.g., casting) and subsequent adjustments. These systems all require expertise and consulting support that is not widely available. In particular, the socket (i.e., the portion of the prosthesis into which the residual limb fits), socket attachment, and alignment aspects of the device seem to be a common problematic area of development.
It is desirable to create a prosthetic device which eliminates the need for complex fabrication and specialized tools or labs, and which can be economically manufactured and distributed on a global basis.
Residual limbs may also grow or otherwise change shape, which may occur rapidly. In some instances, it may be necessary to replace a prosthetic device every six months to a year. It is desirable to create a prosthetic device which is adjustable to provide continued support and comfort as a residual limb changes.